Attachment plug



's. @GILATQMBE ATTACHMENT PLUG Filed Jan; 12. 1920 3 mve wtoz aim.

Patented Uct. l i, l924t.

STANLEY M CLATCHIE, 0F CAMBRIDGE, MASSACHUSETTS, ASSIGIN'OIR- TO MAGNUS ELECTRIC COMPANY, INC., A CORPORATION OF NEW YORK.

ATTACHMENT PLUG.

Application filed January 12, 1920. Serial No.,351,071.

T0 (ZZZ whom it may concern:

Be it known that I, STANLEY MOCLATOi-IIE, a citizen of the United States, residing at Cambridge, in the county of Middlesex and State of Massachusetts, have invented new and useful Improvements in Attachment Plugs, of which the following is a specification.

My invention relates to attachment plugs, and has for its object an improved and simpliiied construction.

Referring to the drawings, Figure 1 is a section of a plug embodying my invention in one form, and Fig. 2 is an elevation showing this plug with its outer threaded shell removed. Figure 3 is a sectional view similar to that of Figure 1, showing the conductors connected to the terminals.

In the form shown my plug comprises a one-piece insulating body 1, having mounted on its forward end the center terminal 2, and threaded onto its middle portion the metallic shell 3. A hand-hold of convenient shape is provided at the rearward end of the insulating body, as indicated. Thru the center of the body is an enlarged passage 4, for the two entering conductors. The center terminal 2 is riveted in a hole of reduced size at the forward terminus of the passage 4. This terminal consists of a post, preferably of brass, having a longitudinal passage 5 adapted to receive the bared end of a conductor 2, and a transverse set-screw 6 adapted to bind this bared end of the conductor in place. It will be evident from the drawing that in order to connect up a conductor to the center terminal it is only necessary to insert the same straight thru to the forward end of the plug, where it passes right into the center terminal and may be bound down with a few turns of the binding-screw 6. This process is simpler than that involved with the now common longitudinal bindingscrew type of center terminal, in which it is necessary to thread the conductor thru a one-sided passage in the base and then it it around under the head of the binding-screw. My terminal also simplifies construction, as it is made of but two parts and does not require a one-sided longitudinal pass thru the end of the base, something which it is awkward to provide for in a one-piece moulded body. Thru one side of the insulating body runs a passage 7. As shown in Fig. 2, this passage communicates at the surface with a groove 8. This groove leads to a channel 9 located at the forward termination of the threaded portion of the body. The metallic shell 3, which forms the side terminal of the plug, is provided with an inner flange 10, adapted to engage the channel 9. To connect up the conductor 3 to the side terminal it is required to pass one end of the same thru the lateral passage 7, and to lay it along the groove 8; its bared end is then laid around in the channel 9, and the shell 3 is screwed on until the flange thereon binds in firm connection with it. The shell may be secured in place by indenting it at the opening 7. Tn passing thru the lateral opening and the groove to the channel 9 the conductor makes several turns. These bends effectually restrain it from pulling out. If the two con ductor terminals are cut of just the same length the center terminal will be found a little slack after the plug has been wired up. Thus any strain placed on the pair of conductors together will be carried by the side conductor terminal alone. found in practice that the strain relief provided in this side terminal is ample to care for any strain likely to be placed upon the conductor cord as a whole. It is well. to double over the bared end of the center conductor before binding it into the center binding-post; this will give a firmer connection.

The present invention atlords a very simple and cheap construction for a one-piece attachment plug. It furthermore comprises an improved center binding terminal, and an improved arrangement for binding the side contact conductor.

It is evident that features of my invention could be used in attachment plugs of other general design than that here shown, and I do not limit myself to the particular construction just described.

I claim as my invention An attachment plug comprising a screwthreaded insulating plug having at one end thereof a. ledge, said plug being provided with a longitudinal conductor receiving passage adapted to receive a pair of conductors and having a radial opening communicating with said passage and terminating in a groove formed upon the periphery of said plug and leading to said ledge, a tubular center terminal arranged within said pas- It will be ill) sage, 451m te m nal b was; wit a head seated directly upon said insulating 11 s an ha in its other e fei e d d 21M: 1 ntqxff iiseiiern f li Sa l. lating plug "whereby the terminal is Tetained ithin said passage, an 011,1;erscre3751- threaded terminal carried by aid i'nsul'ating p and having a flan e ea d 1 w; sa d ledge, and a readily'aecessible radially disa med .SCIjBW earr-ied :by the head of said .cen-

te r aig ix 'aelap e o ngag ,one ,Of 13 1 9 c 1 10 Ret ining the same W hftiheqb iei' fo f said ieenductoi's 131 1 1 1 11 1 1 R0 P s ime; @1 11 radial opening and along said groove to said ledge 15 and ltliere Wrapped around said plug and inai'ntained in position upbn said' ledge by the flange 03:'"sa"id Outer tr rrii nal.

In tness whereof, I have hereunto subse'iibed iny name in the presence of two Wit- 20 ANL EY M QLATQ TQ wim sees 

